The present invention relates to a motor; and, in particular, to a small-size motor which is built into a portable communications instrument (e.g., cellular phone) and is utilized as a source for generating vibrations for calling functions.
Conventionally known as techniques in such a field are those disclosed in Japanese Utility Model Publication No. SHO 62-23248 and Japanese Patent Application Laid-Open No. HEI 11-136901. The former publication proposes a technique in which, while a motor contact for supplying current to a motor brush has a flexibility, its elastic repulsive force is actively utilized. On the other hand, a small-size motor 100 disclosed in the latter publication is made such that it is easily assembled into communications instruments such as a cellular phone. As shown in FIG. 6, the small-size motor 100 has an output shaft 103 to which a weight 104 is secured, whereas a forwardly extending electric terminal 102 is fixed at a barrel 100a of the small-size motor 100 by way of a bracket 105 and a holder 109. If such an electric terminal 102 made of a spring sheet is utilized, then no soldering is necessary when securing the motor 100 onto a circuit board 101, whereby the efficiency of production improves.
However, the above-mentioned conventional motors have a problem as follows. Namely, since the electric terminal 102 obliquely extends forward, the front end of the terminal 102 is grounded on the circuit board 101, whereby the motor 100 would be placed on the circuit board 101 in an unstable state in terms of its weight balance. In cases where the motor is built into other instruments such as a cellular phone in particular, it is necessary for a lid of the cellular phone or the like to press the motor 100 from thereabove. If its assembling operation is carried out in the unstable state shown in FIG. 6, however, then the motor 100 may move leftward in the drawing due to the pressure from the upper side (see the depicted arrow), whereby the terminal 102 may be detached from its predetermined electric contact 101 on the circuit board 101. That is, the motor 100 has a problem that it is not easily assembled into other instruments.
In order to overcome the above-mentioned problem, it is an object of the present invention to provide a motor which can stably be mounted on a circuit board when being assembled into an instrument in particular.
The motor in accordance with the present invention comprises a motor body, an output shaft projecting from a front end of the motor body, and a voltage-supplying terminal provided in the motor body, the terminal having an elastic force in a direction substantially orthogonal to the output shaft and also having a grounding portion disposed near a rear end of the motor body.
At the time of assembling a motor, the present invention intends to place the motor on a circuit board such that the grounding portion of its terminal comes into electric contact with a predetermined position on the circuit board. Namely, since the terminal has an elastic force, it is necessary for the motor to be stable on the circuit board when placed thereon. In the motor in accordance with the present invention, the grounding portion of the terminal is disposed near the rear end of the motor body so as to face the output shaft, whereby the motor attains a supporting balance on the circuit board, thus improving its stability. Also, from the viewpoint of keeping the rotational balance of the output shaft itself, which rotates at a high speed in front of the motor, it is quite meaningful to dispose the grounding portion of the terminal near the rear end of the motor body.
Preferably, in the above-mentioned motor, the terminal is formed by bending an elastic material and comprises a first portion extending substantially parallel to the output shaft from the motor body; a second portion extending substantially parallel to the first portion from a front end of the first portion by way of a bent part; and a third portion, formed with the grounding portion, projecting outward in a curved manner from a rear end of the second portion. When such a configuration is employed, the terminal can be formed with a simple structure at a low cost, whereby its cost of manufacture can be cut down.
Preferably, the above-mentioned motor further comprises a weight eccentrically secured to the output shaft. When such a configuration is employed, a vibrating motor can be constructed appropriately, whereby it becomes easier to assemble the motor into communications instruments such as a cellular phone.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.